The present invention relates to ultra-high molecular weight polymers which are particularly useful as water purification agents. More specifically, the polymers of this invention include partially deacylated poly(N-propionylethylenimines) derived from poly(N-propionylethylenimines) having a weight average molecular weight, M.sub.w, between about 1 million and about 20 million.
U.S. Pat. No. 3,483,141 discloses poly(N-propionylethylenimines) having reduced viscosities between about 0.6 dL/g and about 6.2 dL/g in m-cresol at 25.degree. C.
U.S. Pat. No. 3,833,521 (Karbstein and Scheppers, 1974) discloses a transamidation process for partial deacylation of poly(N-acylalkylenimines) of the formula ##STR1## wherein x is 2 or 3, n is an integer of 10-5,000 and R is a variety of substituents, including alkyl moieties of 1-12 carbon atoms. Karbstein and Scheppers disclose at column 4, line 7, that the deacylated products are useful as auxiliary agents for water treatment. Thus, in view of the structure disclosed by Karbstein and Scheppers, and in view of one of the disclosed uses for the deacylated poly(N-acylalkylenimines), U.S. Pat. No. 3,833,521 discloses that partially deacylated poly(N-propionylethylenimines) are useful as water treatment agents. However, the partially deacylated products of U.S. Pat. No. 3,833,521 are derived from polymers whose M.sub.w is no greater than about 500,000 where R is ethyl. Furthermore, the preferred molecular weight of the precursor polymeric material in U.S. Pat. No. 3,833,521 is only about 30,000 to about 130,000 when poly(N-propionylethylenimines) are employed as precursor polymers. As noted above, the weight average molecular weight of the poly(N-propionylethylenimines) of the present invention from which the deacylated polymers of this invention are derived is between about 1 million and about 20 million.